//------------------------------------------------------------------------------
// deflate.c -- compress data using the deflation algorithm
// Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
// For conditions of distribution and use, see copyright notice in zlib.h
//
//
//  ALGORITHM
//
//      The "deflation" process depends on being able to identify portions
//      of the input text which are identical to earlier input (within a
//      sliding window trailing behind the input currently being processed).
//
//      The most straightforward technique turns out to be the fastest for
//      most input files: try all possible matches and select the longest.
//      The key feature of this algorithm is that insertions into the string
//      dictionary are very simple and thus fast, and deletions are avoided
//      completely. Insertions are performed at each input character, whereas
//      string matches are performed only when the previous match ends. So it
//      is preferable to spend more time in matches to allow very fast string
//      insertions and avoid deletions. The matching algorithm for small
//      strings is inspired from that of Rabin & Karp. A brute force approach
//      is used to find longer strings when a small match has been found.
//      A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
//      (by Leonid Broukhis).
//         A previous version of this file used a more sophisticated algorithm
//      (by Fiala and Greene) which is guaranteed to run in linear amortized
//      time, but has a larger average cost, uses more memory and is patented.
//      However the F&G algorithm may be faster for some highly redundant
//      files if the parameter max_chain_length (described below) is too large.
//
//  ACKNOWLEDGEMENTS
//
//      The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
//      I found it in 'freeze' written by Leonid Broukhis.
//      Thanks to many people for bug reports and testing.
//
//  REFERENCES
//
//      Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
//      Available in http://tools.ietf.org/html/rfc1951
//
//      A description of the Rabin and Karp algorithm is given in the book
//         "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
//
//      Fiala,E.R., and Greene,D.H.
//         Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
//
//
//------------------------------------------------------------------------------
#include "lib/zlib/deflate.h"
#include "utils/macros.h"

namespace zlib {

#if DT_COMPILER_CLANG
  #pragma clang diagnostic push
  #pragma clang diagnostic ignored "-Wconversion"
  #pragma clang diagnostic ignored "-Wcomma"
  #pragma clang diagnostic ignored "-Wpadded"
  #pragma clang diagnostic ignored "-Wold-style-cast"
  #pragma clang diagnostic ignored "-Wsign-conversion"
  #pragma clang diagnostic ignored "-Wunused-const-variable"
  #pragma clang diagnostic ignored "-Wzero-as-null-pointer-constant"
#elif DT_COMPILER_MSVC
  #pragma warning(push)
  #pragma warning(disable : 4244)
#endif


const char deflate_copyright[] =
   " deflate 1.2.11 Copyright 1995-2017 Jean-loup Gailly and Mark Adler ";
/*
  If you use the zlib library in a product, an acknowledgment is welcome
  in the documentation of your product. If for some reason you cannot
  include such an acknowledgment, I would appreciate that you keep this
  copyright string in the executable of your product.
 */

/* ===========================================================================
 *  Function prototypes.
 */
typedef enum {
  need_more,      /* block not completed, need more input or more output */
  block_done,     /* block flush performed */
  finish_started, /* finish started, need only more output at next deflate */
  finish_done     /* finish done, accept no more input or output */
} block_state;

typedef block_state (*compress_func) (deflate_state* s, int flush);
/* Compression function. Returns the block state after the call. */

static int deflateStateCheck(z_stream* strm);
static void slide_hash(deflate_state* s);
static void fill_window(deflate_state* s);
static block_state deflate_stored(deflate_state* s, int flush);
static block_state deflate_fast(deflate_state* s, int flush);
static block_state deflate_slow(deflate_state* s, int flush);
static block_state deflate_rle(deflate_state* s, int flush);
static block_state deflate_huff(deflate_state* s, int flush);
static void lm_init(deflate_state* s);
static void putShortMSB(deflate_state* s, uInt b);
static void flush_pending(z_stream* strm);
static unsigned read_buf(z_stream* strm, Bytef *buf, unsigned size);
static uInt longest_match(deflate_state* s, IPos cur_match);


#define check_match(s, start, match, length)



/* ===========================================================================
 * Local data
 */

#define NIL 0
/* Tail of hash chains */

#ifndef TOO_FAR
#  define TOO_FAR 4096
#endif
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */

/* Values for max_lazy_match, good_match and max_chain_length, depending on
 * the desired pack level (0..9). The values given below have been tuned to
 * exclude worst case performance for pathological files. Better values may be
 * found for specific files.
 */
typedef struct config_s {
   ush good_length; /* reduce lazy search above this match length */
   ush max_lazy;    /* do not perform lazy search above this match length */
   ush nice_length; /* quit search above this match length */
   ush max_chain;
   compress_func func;
} config;

static const config configuration_table[10] = {
/*      good lazy nice chain */
/* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */
/* 1 */ {4,    4,  8,    4, deflate_fast}, /* max speed, no lazy matches */
/* 2 */ {4,    5, 16,    8, deflate_fast},
/* 3 */ {4,    6, 32,   32, deflate_fast},

/* 4 */ {4,    4, 16,   16, deflate_slow},  /* lazy matches */
/* 5 */ {8,   16, 32,   32, deflate_slow},
/* 6 */ {8,   16, 128, 128, deflate_slow},
/* 7 */ {8,   32, 128, 256, deflate_slow},
/* 8 */ {32, 128, 258, 1024, deflate_slow},
/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */

/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
 * meaning.
 */

/* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
#define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0))

/* ===========================================================================
 * Update a hash value with the given input byte
 * IN  assertion: all calls to UPDATE_HASH are made with consecutive input
 *    characters, so that a running hash key can be computed from the previous
 *    key instead of complete recalculation each time.
 */
#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)




/* ===========================================================================
 * Insert string str in the dictionary and set match_head to the previous head
 * of the hash chain (the most recent string with same hash key). Return
 * the previous length of the hash chain.
 * If this file is compiled with -DFASTEST, the compression level is forced
 * to 1, and no hash chains are maintained.
 * IN  assertion: all calls to INSERT_STRING are made with consecutive input
 *    characters and the first MIN_MATCH bytes of str are valid (except for
 *    the last MIN_MATCH-1 bytes of the input file).
 */
#ifdef FASTEST
#define INSERT_STRING(s, str, match_head) \
   (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
  match_head = s->head[s->ins_h], \
  s->head[s->ins_h] = (Pos)(str))
#else
#define INSERT_STRING(s, str, match_head) \
   (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
  match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
  s->head[s->ins_h] = (Pos)(str))
#endif




/* ===========================================================================
 * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
 * prev[] will be initialized on the fly.
 */
#define CLEAR_HASH(s) \
  s->head[s->hash_size-1] = NIL; \
  zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));

/* ===========================================================================
 * Slide the hash table when sliding the window down (could be avoided with 32
 * bit values at the expense of memory usage). We slide even when level == 0 to
 * keep the hash table consistent if we switch back to level > 0 later.
 */
static void slide_hash(deflate_state* s)
{
  unsigned n, m;
  Posf *p;
  uInt wsize = s->w_size;

  n = s->hash_size;
  p = &s->head[n];
  do {
    m = *--p;
    *p = (Pos)(m >= wsize ? m - wsize : NIL);
  } while (--n);
  n = wsize;
  #ifndef FASTEST
    p = &s->prev[n];
    do {
      m = *--p;
      *p = (Pos)(m >= wsize ? m - wsize : NIL);
      /* If n is not on any hash chain, prev[n] is garbage but
       * its value will never be used.
       */
    } while (--n);
  #endif
}




/* ========================================================================= */
int deflateInit_(
  z_stream* strm,
  int level,
  const char *version,
  int stream_size
) {
  return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
             Z_DEFAULT_STRATEGY, version, stream_size);
  /* To do: ignore strm->next_in if we use it as window */
}



/* ========================================================================= */
int deflateInit2_(
  z_stream* strm,
  int  level,
  int  method,
  int  windowBits,
  int  memLevel,
  int  strategy,
  const char *version,
  int stream_size
) {
  deflate_state* s;
  int wrap = 1;
  static const char my_version[] = ZLIB_VERSION;

  ushf *overlay;
  /* We overlay pending_buf and d_buf+l_buf. This works since the average
   * output size for (length,distance) codes is <= 24 bits.
   */

  if (version == Z_NULL || version[0] != my_version[0] ||
    stream_size != sizeof(z_stream)) {
    return Z_VERSION_ERROR;
  }
  if (strm == Z_NULL) return Z_STREAM_ERROR;

  strm->msg = Z_NULL;
  if (strm->zalloc == (alloc_func)0) {
    #ifdef Z_SOLO
      return Z_STREAM_ERROR;
    #else
      strm->zalloc = zcalloc;
      strm->opaque = (voidpf)0;
    #endif
  }
  if (strm->zfree == (free_func)0)
    #ifdef Z_SOLO
      return Z_STREAM_ERROR;
    #else
      strm->zfree = zcfree;
    #endif

  #ifdef FASTEST
    if (level != 0) level = 1;
  #else
    if (level == Z_DEFAULT_COMPRESSION) level = 6;
  #endif

  if (windowBits < 0) { /* suppress zlib wrapper */
    wrap = 0;
    windowBits = -windowBits;
  }
  #ifdef GZIP
    else if (windowBits > 15) {
      wrap = 2;       /* write gzip wrapper instead */
      windowBits -= 16;
    }
  #endif
  if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
    windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
    strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) {
    return Z_STREAM_ERROR;
  }
  if (windowBits == 8) windowBits = 9;  /* until 256-byte window bug fixed */
  s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
  if (s == Z_NULL) return Z_MEM_ERROR;
  strm->state = s;
  s->strm = strm;
  s->status = INIT_STATE;     /* to pass state test in deflateReset() */

  s->wrap = wrap;
  s->gzhead = Z_NULL;
  s->w_bits = (uInt)windowBits;
  s->w_size = 1 << s->w_bits;
  s->w_mask = s->w_size - 1;

  s->hash_bits = (uInt)memLevel + 7;
  s->hash_size = 1 << s->hash_bits;
  s->hash_mask = s->hash_size - 1;
  s->hash_shift =  ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);

  s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
  s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
  s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));

  s->high_water = 0;      /* nothing written to s->window yet */

  s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */

  overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
  s->pending_buf = (uchf *) overlay;
  s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);

  if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
    s->pending_buf == Z_NULL) {
    s->status = FINISH_STATE;
    strm->msg = ERR_MSG(Z_MEM_ERROR);
    deflateEnd (strm);
    return Z_MEM_ERROR;
  }
  s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
  s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;

  s->level = level;
  s->strategy = strategy;
  s->method = (Byte)method;

  return deflateReset(strm);
}




/* =========================================================================
 * Check for a valid deflate stream state. Return 0 if ok, 1 if not.
 */
static int deflateStateCheck(z_stream* strm)
{
  deflate_state* s;
  if (strm == Z_NULL ||
    strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
    return 1;
  s = strm->state;
  if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE &&
                       #ifdef GZIP
                         s->status != GZIP_STATE &&
                       #endif
                       s->status != EXTRA_STATE &&
                       s->status != NAME_STATE &&
                       s->status != COMMENT_STATE &&
                       s->status != HCRC_STATE &&
                       s->status != BUSY_STATE &&
                       s->status != FINISH_STATE))
    return 1;
  return 0;
}




/* ========================================================================= */
static int deflateResetKeep(z_stream* strm)
{
  deflate_state* s;

  if (deflateStateCheck(strm)) {
    return Z_STREAM_ERROR;
  }

  strm->total_in = strm->total_out = 0;
  strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
  strm->data_type = Z_UNKNOWN;

  s = (deflate_state *)strm->state;
  s->pending = 0;
  s->pending_out = s->pending_buf;

  if (s->wrap < 0) {
    s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
  }
  s->status =
  #ifdef GZIP
    s->wrap == 2 ? GZIP_STATE :
  #endif
    s->wrap ? INIT_STATE : BUSY_STATE;
  strm->adler =
  #ifdef GZIP
    s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
  #endif
    adler32(0L, Z_NULL, 0);
  s->last_flush = Z_NO_FLUSH;

  _tr_init(s);

  return Z_OK;
}




/* ========================================================================= */
int deflateReset(z_stream* strm)
{
  int ret;

  ret = deflateResetKeep(strm);
  if (ret == Z_OK)
    lm_init(strm->state);
  return ret;
}




/* =========================================================================
 * For the default windowBits of 15 and memLevel of 8, this function returns
 * a close to exact, as well as small, upper bound on the compressed size.
 * They are coded as constants here for a reason--if the #define's are
 * changed, then this function needs to be changed as well.  The return
 * value for 15 and 8 only works for those exact settings.
 *
 * For any setting other than those defaults for windowBits and memLevel,
 * the value returned is a conservative worst case for the maximum expansion
 * resulting from using fixed blocks instead of stored blocks, which deflate
 * can emit on compressed data for some combinations of the parameters.
 *
 * This function could be more sophisticated to provide closer upper bounds for
 * every combination of windowBits and memLevel.  But even the conservative
 * upper bound of about 14% expansion does not seem onerous for output buffer
 * allocation.
 */
uLong deflateBound(z_stream* strm, uLong sourceLen) {
  deflate_state* s;
  uLong complen, wraplen;

  /* conservative upper bound for compressed data */
  complen = sourceLen +
        ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;

  /* if can't get parameters, return conservative bound plus zlib wrapper */
  if (deflateStateCheck(strm))
    return complen + 6;

  /* compute wrapper length */
  s = strm->state;
  switch (s->wrap) {
  case 0:                                 /* raw deflate */
    wraplen = 0;
    break;
  case 1:                                 /* zlib wrapper */
    wraplen = 6 + (s->strstart ? 4 : 0);
    break;
  #ifdef GZIP
    case 2:                                 /* gzip wrapper */
      wraplen = 18;
      if (s->gzhead != Z_NULL) {          /* user-supplied gzip header */
        Bytef *str;
        if (s->gzhead->extra != Z_NULL)
          wraplen += 2 + s->gzhead->extra_len;
        str = s->gzhead->name;
        if (str != Z_NULL)
          do {
            wraplen++;
          } while (*str++);
        str = s->gzhead->comment;
        if (str != Z_NULL)
          do {
            wraplen++;
          } while (*str++);
        if (s->gzhead->hcrc)
          wraplen += 2;
      }
      break;
  #endif
  default:                                /* for compiler happiness */
    wraplen = 6;
  }

  /* if not default parameters, return conservative bound */
  if (s->w_bits != 15 || s->hash_bits != 8 + 7)
    return complen + wraplen;

  /* default settings: return tight bound for that case */
  return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
       (sourceLen >> 25) + 13 - 6 + wraplen;
}




/* =========================================================================
 * Put a short in the pending buffer. The 16-bit value is put in MSB order.
 * IN assertion: the stream state is correct and there is enough room in
 * pending_buf.
 */
static void putShortMSB (deflate_state* s, uInt b) {
  put_byte(s, (Byte)(b >> 8));
  put_byte(s, (Byte)(b & 0xff));
}




/* =========================================================================
 * Flush as much pending output as possible. All deflate() output, except for
 * some deflate_stored() output, goes through this function so some
 * applications may wish to modify it to avoid allocating a large
 * strm->next_out buffer and copying into it. (See also read_buf()).
 */
static void flush_pending(z_stream* strm) {
  unsigned len;
  deflate_state* s = strm->state;

  _tr_flush_bits(s);
  len = s->pending;
  if (len > strm->avail_out) len = strm->avail_out;
  if (len == 0) return;

  zmemcpy(strm->next_out, s->pending_out, len);
  strm->next_out  += len;
  s->pending_out  += len;
  strm->total_out += len;
  strm->avail_out -= len;
  s->pending      -= len;
  if (s->pending == 0) {
    s->pending_out = s->pending_buf;
  }
}




/* ===========================================================================
 * Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1].
 */
#define HCRC_UPDATE(beg) \
  do { \
    if (s->gzhead->hcrc && s->pending > (beg)) \
      strm->adler = crc32(strm->adler, s->pending_buf + (beg), \
                s->pending - (beg)); \
  } while (0)




/* ========================================================================= */
int deflate(z_stream* strm, int flush)
{
  int old_flush; /* value of flush param for previous deflate call */
  deflate_state* s;

  if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) {
    return Z_STREAM_ERROR;
  }
  s = strm->state;

  if (strm->next_out == Z_NULL ||
    (strm->avail_in != 0 && strm->next_in == Z_NULL) ||
    (s->status == FINISH_STATE && flush != Z_FINISH)) {
    ERR_RETURN(strm, Z_STREAM_ERROR);
  }
  if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);

  old_flush = s->last_flush;
  s->last_flush = flush;

  /* Flush as much pending output as possible */
  if (s->pending != 0) {
    flush_pending(strm);
    if (strm->avail_out == 0) {
      /* Since avail_out is 0, deflate will be called again with
       * more output space, but possibly with both pending and
       * avail_in equal to zero. There won't be anything to do,
       * but this is not an error situation so make sure we
       * return OK instead of BUF_ERROR at next call of deflate:
       */
      s->last_flush = -1;
      return Z_OK;
    }

  /* Make sure there is something to do and avoid duplicate consecutive
   * flushes. For repeated and useless calls with Z_FINISH, we keep
   * returning Z_STREAM_END instead of Z_BUF_ERROR.
   */
  } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) &&
         flush != Z_FINISH) {
    ERR_RETURN(strm, Z_BUF_ERROR);
  }

  /* User must not provide more input after the first FINISH: */
  if (s->status == FINISH_STATE && strm->avail_in != 0) {
    ERR_RETURN(strm, Z_BUF_ERROR);
  }

  /* Write the header */
  if (s->status == INIT_STATE) {
    /* zlib header */
    uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
    uInt level_flags;

    if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
      level_flags = 0;
    else if (s->level < 6)
      level_flags = 1;
    else if (s->level == 6)
      level_flags = 2;
    else
      level_flags = 3;
    header |= (level_flags << 6);
    if (s->strstart != 0) header |= PRESET_DICT;
    header += 31 - (header % 31);

    putShortMSB(s, header);

    /* Save the adler32 of the preset dictionary: */
    if (s->strstart != 0) {
      putShortMSB(s, (uInt)(strm->adler >> 16));
      putShortMSB(s, (uInt)(strm->adler & 0xffff));
    }
    strm->adler = adler32(0L, Z_NULL, 0);
    s->status = BUSY_STATE;

    /* Compression must start with an empty pending buffer */
    flush_pending(strm);
    if (s->pending != 0) {
      s->last_flush = -1;
      return Z_OK;
    }
  }
  #ifdef GZIP
  if (s->status == GZIP_STATE) {
    /* gzip header */
    strm->adler = crc32(0L, Z_NULL, 0);
    put_byte(s, 31);
    put_byte(s, 139);
    put_byte(s, 8);
    if (s->gzhead == Z_NULL) {
      put_byte(s, 0);
      put_byte(s, 0);
      put_byte(s, 0);
      put_byte(s, 0);
      put_byte(s, 0);
      put_byte(s, s->level == 9 ? 2 :
           (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
            4 : 0));
      put_byte(s, OS_CODE);
      s->status = BUSY_STATE;

      /* Compression must start with an empty pending buffer */
      flush_pending(strm);
      if (s->pending != 0) {
        s->last_flush = -1;
        return Z_OK;
      }
    }
    else {
      put_byte(s, (s->gzhead->text ? 1 : 0) +
           (s->gzhead->hcrc ? 2 : 0) +
           (s->gzhead->extra == Z_NULL ? 0 : 4) +
           (s->gzhead->name == Z_NULL ? 0 : 8) +
           (s->gzhead->comment == Z_NULL ? 0 : 16)
           );
      put_byte(s, (Byte)(s->gzhead->time & 0xff));
      put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
      put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
      put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
      put_byte(s, s->level == 9 ? 2 :
           (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
            4 : 0));
      put_byte(s, s->gzhead->os & 0xff);
      if (s->gzhead->extra != Z_NULL) {
        put_byte(s, s->gzhead->extra_len & 0xff);
        put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
      }
      if (s->gzhead->hcrc)
        strm->adler = crc32(strm->adler, s->pending_buf,
                  s->pending);
      s->gzindex = 0;
      s->status = EXTRA_STATE;
    }
  }
  if (s->status == EXTRA_STATE) {
    if (s->gzhead->extra != Z_NULL) {
      ulg beg = s->pending;   /* start of bytes to update crc */
      uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex;
      while (s->pending + left > s->pending_buf_size) {
        uInt copy = s->pending_buf_size - s->pending;
        zmemcpy(s->pending_buf + s->pending,
            s->gzhead->extra + s->gzindex, copy);
        s->pending = s->pending_buf_size;
        HCRC_UPDATE(beg);
        s->gzindex += copy;
        flush_pending(strm);
        if (s->pending != 0) {
          s->last_flush = -1;
          return Z_OK;
        }
        beg = 0;
        left -= copy;
      }
      zmemcpy(s->pending_buf + s->pending,
          s->gzhead->extra + s->gzindex, left);
      s->pending += left;
      HCRC_UPDATE(beg);
      s->gzindex = 0;
    }
    s->status = NAME_STATE;
  }
  if (s->status == NAME_STATE) {
    if (s->gzhead->name != Z_NULL) {
      ulg beg = s->pending;   /* start of bytes to update crc */
      int val;
      do {
        if (s->pending == s->pending_buf_size) {
          HCRC_UPDATE(beg);
          flush_pending(strm);
          if (s->pending != 0) {
            s->last_flush = -1;
            return Z_OK;
          }
          beg = 0;
        }
        val = s->gzhead->name[s->gzindex++];
        put_byte(s, val);
      } while (val != 0);
      HCRC_UPDATE(beg);
      s->gzindex = 0;
    }
    s->status = COMMENT_STATE;
  }
  if (s->status == COMMENT_STATE) {
    if (s->gzhead->comment != Z_NULL) {
      ulg beg = s->pending;   /* start of bytes to update crc */
      int val;
      do {
        if (s->pending == s->pending_buf_size) {
          HCRC_UPDATE(beg);
          flush_pending(strm);
          if (s->pending != 0) {
            s->last_flush = -1;
            return Z_OK;
          }
          beg = 0;
        }
        val = s->gzhead->comment[s->gzindex++];
        put_byte(s, val);
      } while (val != 0);
      HCRC_UPDATE(beg);
    }
    s->status = HCRC_STATE;
  }
  if (s->status == HCRC_STATE) {
    if (s->gzhead->hcrc) {
      if (s->pending + 2 > s->pending_buf_size) {
        flush_pending(strm);
        if (s->pending != 0) {
          s->last_flush = -1;
          return Z_OK;
        }
      }
      put_byte(s, (Byte)(strm->adler & 0xff));
      put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
      strm->adler = crc32(0L, Z_NULL, 0);
    }
    s->status = BUSY_STATE;

    /* Compression must start with an empty pending buffer */
    flush_pending(strm);
    if (s->pending != 0) {
      s->last_flush = -1;
      return Z_OK;
    }
  }
  #endif

  /* Start a new block or continue the current one.
   */
  if (strm->avail_in != 0 || s->lookahead != 0 ||
    (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
    block_state bstate;

    bstate = s->level == 0 ? deflate_stored(s, flush) :
         s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
         s->strategy == Z_RLE ? deflate_rle(s, flush) :
         (*(configuration_table[s->level].func))(s, flush);

    if (bstate == finish_started || bstate == finish_done) {
      s->status = FINISH_STATE;
    }
    if (bstate == need_more || bstate == finish_started) {
      if (strm->avail_out == 0) {
        s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
      }
      return Z_OK;
      /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
       * of deflate should use the same flush parameter to make sure
       * that the flush is complete. So we don't have to output an
       * empty block here, this will be done at next call. This also
       * ensures that for a very small output buffer, we emit at most
       * one empty block.
       */
    }
    if (bstate == block_done) {
      if (flush == Z_PARTIAL_FLUSH) {
        _tr_align(s);
      } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
        _tr_stored_block(s, (char*)0, 0L, 0);
        /* For a full flush, this empty block will be recognized
         * as a special marker by inflate_sync().
         */
        if (flush == Z_FULL_FLUSH) {
          CLEAR_HASH(s);             /* forget history */
          if (s->lookahead == 0) {
            s->strstart = 0;
            s->block_start = 0L;
            s->insert = 0;
          }
        }
      }
      flush_pending(strm);
      if (strm->avail_out == 0) {
        s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
        return Z_OK;
      }
    }
  }

  if (flush != Z_FINISH) return Z_OK;
  if (s->wrap <= 0) return Z_STREAM_END;

  /* Write the trailer */
  #ifdef GZIP
    if (s->wrap == 2) {
      put_byte(s, (Byte)(strm->adler & 0xff));
      put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
      put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
      put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
      put_byte(s, (Byte)(strm->total_in & 0xff));
      put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
      put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
      put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
    }
    else
  #endif
  {
    putShortMSB(s, (uInt)(strm->adler >> 16));
    putShortMSB(s, (uInt)(strm->adler & 0xffff));
  }
  flush_pending(strm);
  /* If avail_out is zero, the application will call deflate again
   * to flush the rest.
   */
  if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
  return s->pending != 0 ? Z_OK : Z_STREAM_END;
}




/* ========================================================================= */
int deflateEnd (z_stream* strm)
{
  int status;

  if (deflateStateCheck(strm)) return Z_STREAM_ERROR;

  status = strm->state->status;

  /* Deallocate in reverse order of allocations: */
  TRY_FREE(strm, strm->state->pending_buf);
  TRY_FREE(strm, strm->state->head);
  TRY_FREE(strm, strm->state->prev);
  TRY_FREE(strm, strm->state->window);

  ZFREE(strm, strm->state);
  strm->state = Z_NULL;

  return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
}




/* ===========================================================================
 * Read a new buffer from the current input stream, update the adler32
 * and total number of bytes read.  All deflate() input goes through
 * this function so some applications may wish to modify it to avoid
 * allocating a large strm->next_in buffer and copying from it.
 * (See also flush_pending()).
 */
static unsigned read_buf(z_stream* strm, Bytef *buf, unsigned size)
{
  unsigned len = strm->avail_in;

  if (len > size) len = size;
  if (len == 0) return 0;

  strm->avail_in  -= len;

  zmemcpy(buf, strm->next_in, len);
  if (strm->state->wrap == 1) {
    strm->adler = adler32(strm->adler, buf, len);
  }
  #ifdef GZIP
    else if (strm->state->wrap == 2) {
      strm->adler = crc32(strm->adler, buf, len);
    }
  #endif
  strm->next_in  += len;
  strm->total_in += len;

  return len;
}




/* ===========================================================================
 * Initialize the "longest match" routines for a new zlib stream
 */
static void lm_init(deflate_state* s)
{
  s->window_size = (ulg)2L*s->w_size;

  CLEAR_HASH(s);

  /* Set the default configuration parameters:
   */
  s->max_lazy_match   = configuration_table[s->level].max_lazy;
  s->good_match       = configuration_table[s->level].good_length;
  s->nice_match       = configuration_table[s->level].nice_length;
  s->max_chain_length = configuration_table[s->level].max_chain;

  s->strstart = 0;
  s->block_start = 0L;
  s->lookahead = 0;
  s->insert = 0;
  s->match_length = s->prev_length = MIN_MATCH-1;
  s->match_available = 0;
  s->ins_h = 0;
}




#ifndef FASTEST
/* ===========================================================================
 * Set match_start to the longest match starting at the given string and
 * return its length. Matches shorter or equal to prev_length are discarded,
 * in which case the result is equal to prev_length and match_start is
 * garbage.
 * IN assertions: cur_match is the head of the hash chain for the current
 *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
 * OUT assertion: the match length is not greater than s->lookahead.
 */
static uInt longest_match(deflate_state* s, IPos cur_match)
{
  unsigned chain_length = s->max_chain_length;/* max hash chain length */
  Bytef *scan = s->window + s->strstart; /* current string */
  Bytef *match;                      /* matched string */
  int len;                           /* length of current match */
  int best_len = (int)s->prev_length;         /* best match length so far */
  int nice_match = s->nice_match;             /* stop if match long enough */
  IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
    s->strstart - (IPos)MAX_DIST(s) : NIL;
  /* Stop when cur_match becomes <= limit. To simplify the code,
   * we prevent matches with the string of window index 0.
   */
  Posf *prev = s->prev;
  uInt wmask = s->w_mask;

  #ifdef UNALIGNED_OK
    /* Compare two bytes at a time. Note: this is not always beneficial.
     * Try with and without -DUNALIGNED_OK to check.
     */
    Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
    ush scan_start = *(ushf*)scan;
    ush scan_end   = *(ushf*)(scan+best_len-1);
  #else
    Bytef *strend = s->window + s->strstart + MAX_MATCH;
    Byte scan_end1  = scan[best_len-1];
    Byte scan_end   = scan[best_len];
  #endif

  /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
   * It is easy to get rid of this optimization if necessary.
   */
  Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");

  /* Do not waste too much time if we already have a good match: */
  if (s->prev_length >= s->good_match) {
    chain_length >>= 2;
  }
  /* Do not look for matches beyond the end of the input. This is necessary
   * to make deflate deterministic.
   */
  if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead;

  Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");

  do {
    Assert(cur_match < s->strstart, "no future");
    match = s->window + cur_match;

    /* Skip to next match if the match length cannot increase
     * or if the match length is less than 2.  Note that the checks below
     * for insufficient lookahead only occur occasionally for performance
     * reasons.  Therefore uninitialized memory will be accessed, and
     * conditional jumps will be made that depend on those values.
     * However the length of the match is limited to the lookahead, so
     * the output of deflate is not affected by the uninitialized values.
     */
    #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
      /* This code assumes sizeof(unsigned short) == 2. Do not use
       * UNALIGNED_OK if your compiler uses a different size.
       */
      if (*(ushf*)(match+best_len-1) != scan_end ||
        *(ushf*)match != scan_start) continue;

      /* It is not necessary to compare scan[2] and match[2] since they are
       * always equal when the other bytes match, given that the hash keys
       * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
       * strstart+3, +5, ... up to strstart+257. We check for insufficient
       * lookahead only every 4th comparison; the 128th check will be made
       * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
       * necessary to put more guard bytes at the end of the window, or
       * to check more often for insufficient lookahead.
       */
      Assert(scan[2] == match[2], "scan[2]?");
      scan++, match++;
      do {
      } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
           *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
           *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
           *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
           scan < strend);
      /* The funny "do {}" generates better code on most compilers */

      /* Here, scan <= window+strstart+257 */
      Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
      if (*scan == *match) scan++;

      len = (MAX_MATCH - 1) - (int)(strend-scan);
      scan = strend - (MAX_MATCH-1);

    #else /* UNALIGNED_OK */

      if (match[best_len]   != scan_end  ||
        match[best_len-1] != scan_end1 ||
        *match            != *scan     ||
        *++match          != scan[1])      continue;

      /* The check at best_len-1 can be removed because it will be made
       * again later. (This heuristic is not always a win.)
       * It is not necessary to compare scan[2] and match[2] since they
       * are always equal when the other bytes match, given that
       * the hash keys are equal and that HASH_BITS >= 8.
       */
      scan += 2, match++;
      Assert(*scan == *match, "match[2]?");

      /* We check for insufficient lookahead only every 8th comparison;
       * the 256th check will be made at strstart+258.
       */
      do {
      } while (*++scan == *++match && *++scan == *++match &&
           *++scan == *++match && *++scan == *++match &&
           *++scan == *++match && *++scan == *++match &&
           *++scan == *++match && *++scan == *++match &&
           scan < strend);

      Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");

      len = MAX_MATCH - (int)(strend - scan);
      scan = strend - MAX_MATCH;

    #endif /* UNALIGNED_OK */

    if (len > best_len) {
      s->match_start = cur_match;
      best_len = len;
      if (len >= nice_match) break;
      #ifdef UNALIGNED_OK
        scan_end = *(ushf*)(scan+best_len-1);
      #else
        scan_end1  = scan[best_len-1];
        scan_end   = scan[best_len];
      #endif
    }
  } while ((cur_match = prev[cur_match & wmask]) > limit
       && --chain_length != 0);

  if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
  return s->lookahead;
}

#else /* FASTEST */

/* ---------------------------------------------------------------------------
 * Optimized version for FASTEST only
 */
static uInt longest_match(deflate_state* s, IPos cur_match)
{
  register Bytef *scan = s->window + s->strstart; /* current string */
  register Bytef *match;                       /* matched string */
  register int len;                           /* length of current match */
  register Bytef *strend = s->window + s->strstart + MAX_MATCH;

  /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
   * It is easy to get rid of this optimization if necessary.
   */
  Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");

  Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");

  Assert(cur_match < s->strstart, "no future");

  match = s->window + cur_match;

  /* Return failure if the match length is less than 2:
   */
  if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;

  /* The check at best_len-1 can be removed because it will be made
   * again later. (This heuristic is not always a win.)
   * It is not necessary to compare scan[2] and match[2] since they
   * are always equal when the other bytes match, given that
   * the hash keys are equal and that HASH_BITS >= 8.
   */
  scan += 2, match += 2;
  Assert(*scan == *match, "match[2]?");

  /* We check for insufficient lookahead only every 8th comparison;
   * the 256th check will be made at strstart+258.
   */
  do {
  } while (*++scan == *++match && *++scan == *++match &&
       *++scan == *++match && *++scan == *++match &&
       *++scan == *++match && *++scan == *++match &&
       *++scan == *++match && *++scan == *++match &&
       scan < strend);

  Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");

  len = MAX_MATCH - (int)(strend - scan);

  if (len < MIN_MATCH) return MIN_MATCH - 1;

  s->match_start = cur_match;
  return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
}

#endif /* FASTEST */




/* ===========================================================================
 * Fill the window when the lookahead becomes insufficient.
 * Updates strstart and lookahead.
 *
 * IN assertion: lookahead < MIN_LOOKAHEAD
 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
 *    At least one byte has been read, or avail_in == 0; reads are
 *    performed for at least two bytes (required for the zip translate_eol
 *    option -- not supported here).
 */
static void fill_window(deflate_state* s)
{
  unsigned n;
  unsigned more;    /* Amount of free space at the end of the window. */
  uInt wsize = s->w_size;

  Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead");

  do {
    more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);

    /* Deal with !@#$% 64K limit: */
    if (sizeof(int) <= 2) {
      if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
        more = wsize;

      } else if (more == (unsigned)(-1)) {
        /* Very unlikely, but possible on 16 bit machine if
         * strstart == 0 && lookahead == 1 (input done a byte at time)
         */
        more--;
      }
    }

    /* If the window is almost full and there is insufficient lookahead,
     * move the upper half to the lower one to make room in the upper half.
     */
    if (s->strstart >= wsize+MAX_DIST(s)) {

      zmemcpy(s->window, s->window+wsize, (unsigned)wsize - more);
      s->match_start -= wsize;
      s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
      s->block_start -= (long) wsize;
      slide_hash(s);
      more += wsize;
    }
    if (s->strm->avail_in == 0) break;

    /* If there was no sliding:
     *    strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
     *    more == window_size - lookahead - strstart
     * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
     * => more >= window_size - 2*WSIZE + 2
     * In the BIG_MEM or MMAP case (not yet supported),
     *   window_size == input_size + MIN_LOOKAHEAD  &&
     *   strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
     * Otherwise, window_size == 2*WSIZE so more >= 2.
     * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
     */
    Assert(more >= 2, "more < 2");

    n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
    s->lookahead += n;

    /* Initialize the hash value now that we have some input: */
    if (s->lookahead + s->insert >= MIN_MATCH) {
      uInt str = s->strstart - s->insert;
      s->ins_h = s->window[str];
      UPDATE_HASH(s, s->ins_h, s->window[str + 1]);
      #if MIN_MATCH != 3
        Call UPDATE_HASH() MIN_MATCH-3 more times
      #endif
      while (s->insert) {
        UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
        #ifndef FASTEST
          s->prev[str & s->w_mask] = s->head[s->ins_h];
        #endif
        s->head[s->ins_h] = (Pos)str;
        str++;
        s->insert--;
        if (s->lookahead + s->insert < MIN_MATCH)
          break;
      }
    }
    /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
     * but this is not important since only literal bytes will be emitted.
     */

  } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);

  /* If the WIN_INIT bytes after the end of the current data have never been
   * written, then zero those bytes in order to avoid memory check reports of
   * the use of uninitialized (or uninitialised as Julian writes) bytes by
   * the longest match routines.  Update the high water mark for the next
   * time through here.  WIN_INIT is set to MAX_MATCH since the longest match
   * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
   */
  if (s->high_water < s->window_size) {
    ulg curr = s->strstart + (ulg)(s->lookahead);
    ulg init;

    if (s->high_water < curr) {
      /* Previous high water mark below current data -- zero WIN_INIT
       * bytes or up to end of window, whichever is less.
       */
      init = s->window_size - curr;
      if (init > WIN_INIT)
        init = WIN_INIT;
      zmemzero(s->window + curr, (unsigned)init);
      s->high_water = curr + init;
    }
    else if (s->high_water < (ulg)curr + WIN_INIT) {
      /* High water mark at or above current data, but below current data
       * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
       * to end of window, whichever is less.
       */
      init = (ulg)curr + WIN_INIT - s->high_water;
      if (init > s->window_size - s->high_water)
        init = s->window_size - s->high_water;
      zmemzero(s->window + s->high_water, (unsigned)init);
      s->high_water += init;
    }
  }

  Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
       "not enough room for search");
}




/* ===========================================================================
 * Flush the current block, with given end-of-file flag.
 * IN assertion: strstart is set to the end of the current match.
 */
#define FLUSH_BLOCK_ONLY(s, last) { \
   _tr_flush_block(s, (s->block_start >= 0L ? \
           (charf *)&s->window[(unsigned)s->block_start] : \
           (charf *)Z_NULL), \
        (ulg)((long)s->strstart - s->block_start), \
        (last)); \
   s->block_start = s->strstart; \
   flush_pending(s->strm); \
   Tracev((stderr,"[FLUSH]")); \
}

/* Same but force premature exit if necessary. */
#define FLUSH_BLOCK(s, last) { \
   FLUSH_BLOCK_ONLY(s, last); \
   if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
}

/* Maximum stored block length in deflate format (not including header). */
#define MAX_STORED 65535

/* Minimum of a and b. */
#define MIN(a, b) ((a) > (b) ? (b) : (a))




/* ===========================================================================
 * Copy without compression as much as possible from the input stream, return
 * the current block state.
 *
 * In case deflateParams() is used to later switch to a non-zero compression
 * level, s->matches (otherwise unused when storing) keeps track of the number
 * of hash table slides to perform. If s->matches is 1, then one hash table
 * slide will be done when switching. If s->matches is 2, the maximum value
 * allowed here, then the hash table will be cleared, since two or more slides
 * is the same as a clear.
 *
 * deflate_stored() is written to minimize the number of times an input byte is
 * copied. It is most efficient with large input and output buffers, which
 * maximizes the opportunites to have a single copy from next_in to next_out.
 */
static block_state deflate_stored(deflate_state* s, int flush)
{
  /* Smallest worthy block size when not flushing or finishing. By default
   * this is 32K. This can be as small as 507 bytes for memLevel == 1. For
   * large input and output buffers, the stored block size will be larger.
   */
  unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size);

  /* Copy as many min_block or larger stored blocks directly to next_out as
   * possible. If flushing, copy the remaining available input to next_out as
   * stored blocks, if there is enough space.
   */
  unsigned len, left, have, last = 0;
  unsigned used = s->strm->avail_in;
  do {
    /* Set len to the maximum size block that we can copy directly with the
     * available input data and output space. Set left to how much of that
     * would be copied from what's left in the window.
     */
    len = MAX_STORED;       /* maximum deflate stored block length */
    have = (s->bi_valid + 42) >> 3;         /* number of header bytes */
    if (s->strm->avail_out < have)          /* need room for header */
      break;
      /* maximum stored block length that will fit in avail_out: */
    have = s->strm->avail_out - have;
    left = s->strstart - s->block_start;    /* bytes left in window */
    if (len > (ulg)left + s->strm->avail_in)
      len = left + s->strm->avail_in;     /* limit len to the input */
    if (len > have)
      len = have;                         /* limit len to the output */

    /* If the stored block would be less than min_block in length, or if
     * unable to copy all of the available input when flushing, then try
     * copying to the window and the pending buffer instead. Also don't
     * write an empty block when flushing -- deflate() does that.
     */
    if (len < min_block && ((len == 0 && flush != Z_FINISH) ||
                flush == Z_NO_FLUSH ||
                len != left + s->strm->avail_in))
      break;

    /* Make a dummy stored block in pending to get the header bytes,
     * including any pending bits. This also updates the debugging counts.
     */
    last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0;
    _tr_stored_block(s, (char *)0, 0L, last);

    /* Replace the lengths in the dummy stored block with len. */
    s->pending_buf[s->pending - 4] = len;
    s->pending_buf[s->pending - 3] = len >> 8;
    s->pending_buf[s->pending - 2] = ~len;
    s->pending_buf[s->pending - 1] = ~len >> 8;

    /* Write the stored block header bytes. */
    flush_pending(s->strm);

    /* Copy uncompressed bytes from the window to next_out. */
    if (left) {
      if (left > len)
        left = len;
      zmemcpy(s->strm->next_out, s->window + s->block_start, left);
      s->strm->next_out += left;
      s->strm->avail_out -= left;
      s->strm->total_out += left;
      s->block_start += left;
      len -= left;
    }

    /* Copy uncompressed bytes directly from next_in to next_out, updating
     * the check value.
     */
    if (len) {
      read_buf(s->strm, s->strm->next_out, len);
      s->strm->next_out += len;
      s->strm->avail_out -= len;
      s->strm->total_out += len;
    }
  } while (last == 0);

  /* Update the sliding window with the last s->w_size bytes of the copied
   * data, or append all of the copied data to the existing window if less
   * than s->w_size bytes were copied. Also update the number of bytes to
   * insert in the hash tables, in the event that deflateParams() switches to
   * a non-zero compression level.
   */
  used -= s->strm->avail_in;      /* number of input bytes directly copied */
  if (used) {
    /* If any input was used, then no unused input remains in the window,
     * therefore s->block_start == s->strstart.
     */
    if (used >= s->w_size) {    /* supplant the previous history */
      s->matches = 2;         /* clear hash */
      zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
      s->strstart = s->w_size;
    }
    else {
      if (s->window_size - s->strstart <= used) {
        /* Slide the window down. */
        s->strstart -= s->w_size;
        zmemcpy(s->window, s->window + s->w_size, s->strstart);
        if (s->matches < 2)
          s->matches++;   /* add a pending slide_hash() */
      }
      zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);
      s->strstart += used;
    }
    s->block_start = s->strstart;
    s->insert += MIN(used, s->w_size - s->insert);
  }
  if (s->high_water < s->strstart)
    s->high_water = s->strstart;

  /* If the last block was written to next_out, then done. */
  if (last)
    return finish_done;

  /* If flushing and all input has been consumed, then done. */
  if (flush != Z_NO_FLUSH && flush != Z_FINISH &&
    s->strm->avail_in == 0 && (long)s->strstart == s->block_start)
    return block_done;

  /* Fill the window with any remaining input. */
  have = s->window_size - s->strstart - 1;
  if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) {
    /* Slide the window down. */
    s->block_start -= s->w_size;
    s->strstart -= s->w_size;
    zmemcpy(s->window, s->window + s->w_size, s->strstart);
    if (s->matches < 2)
      s->matches++;           /* add a pending slide_hash() */
    have += s->w_size;          /* more space now */
  }
  if (have > s->strm->avail_in)
    have = s->strm->avail_in;
  if (have) {
    read_buf(s->strm, s->window + s->strstart, have);
    s->strstart += have;
  }
  if (s->high_water < s->strstart)
    s->high_water = s->strstart;

  /* There was not enough avail_out to write a complete worthy or flushed
   * stored block to next_out. Write a stored block to pending instead, if we
   * have enough input for a worthy block, or if flushing and there is enough
   * room for the remaining input as a stored block in the pending buffer.
   */
  have = (s->bi_valid + 42) >> 3;         /* number of header bytes */
    /* maximum stored block length that will fit in pending: */
  have = MIN(s->pending_buf_size - have, MAX_STORED);
  min_block = MIN(have, s->w_size);
  left = s->strstart - s->block_start;
  if (left >= min_block ||
    ((left || flush == Z_FINISH) && flush != Z_NO_FLUSH &&
     s->strm->avail_in == 0 && left <= have)) {
    len = MIN(left, have);
    last = flush == Z_FINISH && s->strm->avail_in == 0 &&
         len == left ? 1 : 0;
    _tr_stored_block(s, (charf *)s->window + s->block_start, len, last);
    s->block_start += len;
    flush_pending(s->strm);
  }

  /* We've done all we can with the available input and output. */
  return last ? finish_started : need_more;
}




/* ===========================================================================
 * Compress as much as possible from the input stream, return the current
 * block state.
 * This function does not perform lazy evaluation of matches and inserts
 * new strings in the dictionary only for unmatched strings or for short
 * matches. It is used only for the fast compression options.
 */
static block_state deflate_fast(deflate_state* s, int flush)
{
  IPos hash_head;       /* head of the hash chain */
  int bflush;           /* set if current block must be flushed */

  for (;;) {
    /* Make sure that we always have enough lookahead, except
     * at the end of the input file. We need MAX_MATCH bytes
     * for the next match, plus MIN_MATCH bytes to insert the
     * string following the next match.
     */
    if (s->lookahead < MIN_LOOKAHEAD) {
      fill_window(s);
      if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
        return need_more;
      }
      if (s->lookahead == 0) break; /* flush the current block */
    }

    /* Insert the string window[strstart .. strstart+2] in the
     * dictionary, and set hash_head to the head of the hash chain:
     */
    hash_head = NIL;
    if (s->lookahead >= MIN_MATCH) {
      INSERT_STRING(s, s->strstart, hash_head);
    }

    /* Find the longest match, discarding those <= prev_length.
     * At this point we have always match_length < MIN_MATCH
     */
    if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
      /* To simplify the code, we prevent matches with the string
       * of window index 0 (in particular we have to avoid a match
       * of the string with itself at the start of the input file).
       */
      s->match_length = longest_match (s, hash_head);
      /* longest_match() sets match_start */
    }
    if (s->match_length >= MIN_MATCH) {
      check_match(s, s->strstart, s->match_start, s->match_length);

      _tr_tally_dist(s, s->strstart - s->match_start,
               s->match_length - MIN_MATCH, bflush);

      s->lookahead -= s->match_length;

      /* Insert new strings in the hash table only if the match length
       * is not too large. This saves time but degrades compression.
       */
      #ifndef FASTEST
        if (s->match_length <= s->max_insert_length &&
          s->lookahead >= MIN_MATCH) {
          s->match_length--; /* string at strstart already in table */
          do {
            s->strstart++;
            INSERT_STRING(s, s->strstart, hash_head);
            /* strstart never exceeds WSIZE-MAX_MATCH, so there are
             * always MIN_MATCH bytes ahead.
             */
          } while (--s->match_length != 0);
          s->strstart++;
        } else
      #endif
      {
        s->strstart += s->match_length;
        s->match_length = 0;
        s->ins_h = s->window[s->strstart];
        UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
        #if MIN_MATCH != 3
          Call UPDATE_HASH() MIN_MATCH-3 more times
        #endif
        /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
         * matter since it will be recomputed at next deflate call.
         */
      }
    } else {
      /* No match, output a literal byte */
      Tracevv((stderr,"%c", s->window[s->strstart]));
      _tr_tally_lit (s, s->window[s->strstart], bflush);
      s->lookahead--;
      s->strstart++;
    }
    if (bflush) FLUSH_BLOCK(s, 0);
  }
  s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
  if (flush == Z_FINISH) {
    FLUSH_BLOCK(s, 1);
    return finish_done;
  }
  if (s->last_lit)
    FLUSH_BLOCK(s, 0);
  return block_done;
}




/* ===========================================================================
 * Same as above, but achieves better compression. We use a lazy
 * evaluation for matches: a match is finally adopted only if there is
 * no better match at the next window position.
 */
#ifndef FASTEST
static block_state deflate_slow(deflate_state* s, int flush)
{
  IPos hash_head;          /* head of hash chain */
  int bflush;              /* set if current block must be flushed */

  /* Process the input block. */
  for (;;) {
    /* Make sure that we always have enough lookahead, except
     * at the end of the input file. We need MAX_MATCH bytes
     * for the next match, plus MIN_MATCH bytes to insert the
     * string following the next match.
     */
    if (s->lookahead < MIN_LOOKAHEAD) {
      fill_window(s);
      if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
        return need_more;
      }
      if (s->lookahead == 0) break; /* flush the current block */
    }

    /* Insert the string window[strstart .. strstart+2] in the
     * dictionary, and set hash_head to the head of the hash chain:
     */
    hash_head = NIL;
    if (s->lookahead >= MIN_MATCH) {
      INSERT_STRING(s, s->strstart, hash_head);
    }

    /* Find the longest match, discarding those <= prev_length.
     */
    s->prev_length = s->match_length, s->prev_match = s->match_start;
    s->match_length = MIN_MATCH-1;

    if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
      s->strstart - hash_head <= MAX_DIST(s)) {
      /* To simplify the code, we prevent matches with the string
       * of window index 0 (in particular we have to avoid a match
       * of the string with itself at the start of the input file).
       */
      s->match_length = longest_match (s, hash_head);
      /* longest_match() sets match_start */

      if (s->match_length <= 5 && (s->strategy == Z_FILTERED
        #if TOO_FAR <= 32767
          || (s->match_length == MIN_MATCH &&
            s->strstart - s->match_start > TOO_FAR)
        #endif
        )) {

        /* If prev_match is also MIN_MATCH, match_start is garbage
         * but we will ignore the current match anyway.
         */
        s->match_length = MIN_MATCH-1;
      }
    }
    /* If there was a match at the previous step and the current
     * match is not better, output the previous match:
     */
    if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
      uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
      /* Do not insert strings in hash table beyond this. */

      check_match(s, s->strstart-1, s->prev_match, s->prev_length);

      _tr_tally_dist(s, s->strstart -1 - s->prev_match,
               s->prev_length - MIN_MATCH, bflush);

      /* Insert in hash table all strings up to the end of the match.
       * strstart-1 and strstart are already inserted. If there is not
       * enough lookahead, the last two strings are not inserted in
       * the hash table.
       */
      s->lookahead -= s->prev_length-1;
      s->prev_length -= 2;
      do {
        if (++s->strstart <= max_insert) {
          INSERT_STRING(s, s->strstart, hash_head);
        }
      } while (--s->prev_length != 0);
      s->match_available = 0;
      s->match_length = MIN_MATCH-1;
      s->strstart++;

      if (bflush) FLUSH_BLOCK(s, 0);

    } else if (s->match_available) {
      /* If there was no match at the previous position, output a
       * single literal. If there was a match but the current match
       * is longer, truncate the previous match to a single literal.
       */
      Tracevv((stderr,"%c", s->window[s->strstart-1]));
      _tr_tally_lit(s, s->window[s->strstart-1], bflush);
      if (bflush) {
        FLUSH_BLOCK_ONLY(s, 0);
      }
      s->strstart++;
      s->lookahead--;
      if (s->strm->avail_out == 0) return need_more;
    } else {
      /* There is no previous match to compare with, wait for
       * the next step to decide.
       */
      s->match_available = 1;
      s->strstart++;
      s->lookahead--;
    }
  }
  Assert (flush != Z_NO_FLUSH, "no flush?");
  if (s->match_available) {
    Tracevv((stderr,"%c", s->window[s->strstart-1]));
    _tr_tally_lit(s, s->window[s->strstart-1], bflush);
    s->match_available = 0;
  }
  s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
  if (flush == Z_FINISH) {
    FLUSH_BLOCK(s, 1);
    return finish_done;
  }
  if (s->last_lit)
    FLUSH_BLOCK(s, 0);
  return block_done;
}
#endif /* FASTEST */





/* ===========================================================================
 * For Z_RLE, simply look for runs of bytes, generate matches only of distance
 * one.  Do not maintain a hash table.  (It will be regenerated if this run of
 * deflate switches away from Z_RLE.)
 */
static block_state deflate_rle(deflate_state* s, int flush)
{
  int bflush;             /* set if current block must be flushed */
  uInt prev;              /* byte at distance one to match */
  Bytef *scan, *strend;   /* scan goes up to strend for length of run */

  for (;;) {
    /* Make sure that we always have enough lookahead, except
     * at the end of the input file. We need MAX_MATCH bytes
     * for the longest run, plus one for the unrolled loop.
     */
    if (s->lookahead <= MAX_MATCH) {
      fill_window(s);
      if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) {
        return need_more;
      }
      if (s->lookahead == 0) break; /* flush the current block */
    }

    /* See how many times the previous byte repeats */
    s->match_length = 0;
    if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
      scan = s->window + s->strstart - 1;
      prev = *scan;
      if (prev == *++scan && prev == *++scan && prev == *++scan) {
        strend = s->window + s->strstart + MAX_MATCH;
        do {
        } while (prev == *++scan && prev == *++scan &&
             prev == *++scan && prev == *++scan &&
             prev == *++scan && prev == *++scan &&
             prev == *++scan && prev == *++scan &&
             scan < strend);
        s->match_length = MAX_MATCH - (uInt)(strend - scan);
        if (s->match_length > s->lookahead)
          s->match_length = s->lookahead;
      }
      Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan");
    }

    /* Emit match if have run of MIN_MATCH or longer, else emit literal */
    if (s->match_length >= MIN_MATCH) {
      check_match(s, s->strstart, s->strstart - 1, s->match_length);

      _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);

      s->lookahead -= s->match_length;
      s->strstart += s->match_length;
      s->match_length = 0;
    } else {
      /* No match, output a literal byte */
      Tracevv((stderr,"%c", s->window[s->strstart]));
      _tr_tally_lit (s, s->window[s->strstart], bflush);
      s->lookahead--;
      s->strstart++;
    }
    if (bflush) FLUSH_BLOCK(s, 0);
  }
  s->insert = 0;
  if (flush == Z_FINISH) {
    FLUSH_BLOCK(s, 1);
    return finish_done;
  }
  if (s->last_lit)
    FLUSH_BLOCK(s, 0);
  return block_done;
}




/* ===========================================================================
 * For Z_HUFFMAN_ONLY, do not look for matches.  Do not maintain a hash table.
 * (It will be regenerated if this run of deflate switches away from Huffman.)
 */
static block_state deflate_huff(deflate_state* s, int flush)
{
  int bflush;             /* set if current block must be flushed */

  for (;;) {
    /* Make sure that we have a literal to write. */
    if (s->lookahead == 0) {
      fill_window(s);
      if (s->lookahead == 0) {
        if (flush == Z_NO_FLUSH)
          return need_more;
        break;      /* flush the current block */
      }
    }

    /* Output a literal byte */
    s->match_length = 0;
    Tracevv((stderr,"%c", s->window[s->strstart]));
    _tr_tally_lit (s, s->window[s->strstart], bflush);
    s->lookahead--;
    s->strstart++;
    if (bflush) FLUSH_BLOCK(s, 0);
  }
  s->insert = 0;
  if (flush == Z_FINISH) {
    FLUSH_BLOCK(s, 1);
    return finish_done;
  }
  if (s->last_lit)
    FLUSH_BLOCK(s, 0);
  return block_done;
}


#if DT_COMPILER_CLANG
  #pragma clang diagnostic pop
#elif DT_COMPILER_MSVC
  #pragma warning(pop)
#endif

} // namespace zlib
